An Organic Light Emitting Diode (OLED) display is a current-driven display and needs to be driven by a stable current to emit light. For reasons such as those occurring in a manufacturing process or from device aging, a pixel compensation circuit capable of compensating a threshold voltage (Vth) of a driving transistor is generally used in the OLED display to drive OLED to emit light. By compensating the threshold voltage, a problem of display non-uniformity caused by a drift of the threshold voltage of the driving transistor can be effectively improved.
However, how to further improve uniformity of a displayed image based on the existing pixel compensation circuit is a technical problem which needs to be solved by one skilled in the art urgently.